The present invention relates to a volume compensation accumulator apparatus for, in a suspension system connecting hydraulic cylinders each disposed between a wheel and a vehicle body through a conduit, compensating a volume of hydraulic fluid through a connection to the conduit of the suspension system, and the suspension system using the same.
There is known a suspension system controlling a vibration and a posture of a vehicle body by connecting the hydraulic cylinders mounted at the front right, front left, rear right and rear left wheels of the vehicle through a conduit, and controlling a flow of the hydraulic fluid between the hydraulic cylinders caused by, for example, a posture change of the vehicle body with use of an accumulator and a damping valve, as disclosed in, for example, Japanese Patent Application Domestic Announcement No. 2006-519124. This suspension system includes a volume compensation accumulator connected to the conduit via a volume compensation orifice having a sufficiently small flow passage area for compensating a change in the volume of the hydraulic fluid caused from, for example, the movable load of the vehicle and the temperature. According to this configuration, when a transient flow of the hydraulic fluid is generated by a posture change and a vibration of the vehicle body, the volume compensation orifice exerts a large resistance, thereby blocking a flow of the hydraulic fluid to the volume compensation accumulator. When a change in the volume of the hydraulic fluid in the conduit occurs on a regular basis based on, for example, the movable load of the vehicle and the temperature, the volume compensation orifice allows a flow of the hydraulic fluid to the volume compensation accumulator, thereby compensating the volume of the hydraulic fluid.
However, there is a problem regarding the volume compensation orifice; that is, it is difficult to achieve the required precision, since the volume compensation orifice should have an extremely small flow passage area.